1. Technical Field
The present invention relates to a plasma display device. More particularly, the present invention relates to a plasma display device including a chassis base having a boss that exhibits an enhanced fastening strength. The boss may be used to securely mount a printed circuit board assembly to the chassis base.
2. Related Art
In general, a plasma display device includes a plasma display panel that displays a visible image. The plasma display panel operates by exciting phosphors using vacuum ultraviolet light generated through gas discharge in a discharge cell. Plasma display devices may exhibit a number of desirable characteristics, such as excellent display capacity, brightness, contrast, viewing angle, etc.
The plasma display device may include the plasma display panel for displaying the visible image, as well as a chassis base for supporting the plasma display panel, printed circuit board assemblies mounted to a surface of the chassis base opposite to the plasma display panel, and a case for enclosing the plasma display panel, the chassis base and the printed circuit board assemblies, i.e., defining exterior surfaces of the plasma display device.
The case may include a front cover, located at the front side of the plasma display panel, and a rear cover, located at the rear side of the plasma display panel. Typically, the front and rear covers may be reversibly assembled and disassembled from each other.
The printed circuit board assemblies mounted to the chassis base may include one or more of the following: a power supply board assembly, an image processing board assembly, a logic board assembly, an address buffer board assembly, a sustain electrode driving board assembly, and a scan electrode driving board assembly. These printed circuit board assemblies may be formed by mounting components and elements on printed circuit boards according to predetermined designs.
The chassis base may include a plurality of mounting bosses, and the printed circuit board assemblies may fastened to the bosses by fasteners, e.g., screws. The printed circuit board assemblies may be electrically connected to the plasma display panel, e.g., by flexible printed circuits, to drive the plasma display panel.
The mounting boss may have a circular cross-section and may include a fastening part to which the fastener, e.g., a screw, is fastened. The boss may also include a pressing part which is integrally formed at the rear end of the fastening part. The pressing part of the boss may be pressed into the chassis base. The boss may further include a pressing groove formed in the boss between the fastening part and the pressing part. The pressing groove may be formed in a circumferential direction, i.e., around the boss. Upon installation of the boss into the chassis base, a portion of the chassis base may be formed into the pressing groove from the action of pressing the boss into the chassis base.
The chassis base may have the plasma display panel mounted to a front surface thereof, and the boss may be pressed through the chassis base from the front surface, in order to mount components to the opposing, i.e., rear, surface of the chassis base. The boss may be installed through a mounting hole formed in the chassis base in a location corresponding to the fastening position of a printed board assembly.
In detail, the boss may be installed through the mounting hole in the chassis base and the pressing part of the boss may be pressed into the front surface of the chassis base. Thus, a portion of the chassis base adjacent to the mounting hole and pressed by the pressing part may be deformed, i.e., the material of the chassis base may be displaced by the pressing of the pressing part into the chassis base. The deformation may cause the chassis base material to be displaced into the pressing groove. Thus, the portion of the chassis base adjacent to the mounting hole may be deformed with high density and may be fitted into the pressing groove of the boss to form a fitting part of the chassis base, interlocking with the boss and thereby fixing the boss in place in the chassis base.
Recently, in order to reduce the weight of plasma display devices, there has been a drive to reduce the thickness of the material used for the chassis base. However, reducing the thickness of the chassis base may limit the fastening strength of the boss, since it is fastened to the chassis base by being pressed into the material. In particular, the inner surface of the boss pressing groove is formed parallel to the center line of the boss, and the chassis base fitting portion is not completely fastened to the pressing groove. That is, a space may remain between the inner surface of the boss pressing groove and the chassis base fitting part after pressing the boss into the chassis base.
One result of this reduction in strength is that the boss may pull out or loosen. In particular, while the conventional structure may provide satisfactory strength against forces acting in the same direction as which the boss was pressed, forces acting in the direction opposite to the pressing direction may overcome the limited strength of the boss in this regard. For example, the contact resistance surface, formed where the chassis base fitting portion is deformed into the boss pressing groove, may be too narrow. Thus, while the boss may not be drawn out in the pressing direction, the resistance to separation in the opposite direction may be poor, such that a desired fastening strength cannot be obtained.